a) Field of the Invention
This invention relates to an optical imaging system. More specifically it relates to such a system in which a partial variator system is used in conjunction with either or both a front optical systems and a rear optical system, in which either the front optical system, the rear optical system, or both the front and rear optical systems provide one or more optical element in conjunction with the partial variator system to form an afocal variator.
b) Discussion of the Prior Art
"Varios" and "variators" are well known and useful optical systems. Such systems have found use primarily in zoom lens systems and in projectors, for example, to change the size of a projected image on a screen. Afocal variators of the specific type described in the present application have been known and in commercial use and on sale, by themselves, for at least twenty years, for example for use in projector lenses to alter the size of a projected image on a screen. The applicant of the present invention has taught the use of variators as focusing devices in the following listed related applications in conjunction with both refractive and partially obscured reflective optical systems. However, in all such instances, such variator optical systems have been used as complete and separate subsystems, independent of the front and of the rear imaging optical systems with which they are interfaced. That is, that while the front and the rear imaging optical systems are taught to be connected to and integrated with the variator, as modules, neither the front optical system, nor the rear optical system, nor the combined front and rear optical systems, as previously taught by applicant, does any portion of those optical systems provide an element of the afocal variator. That is, in the prior art, no portion of the front optical system, nor of the rear optical system, nor of the combined front and rear optical systems are taught or suggested to be subsumed into nor form a working portion of the afocal variator.
Applicant's related applications include U.S. Pat. No. 5,191,469 entitled AFOCAL VARIATION FOCUSING SYSTEM FOR MIRRORED OPTICAL SYSTEMS, U.S. Pat. No. 5,054,896 entitled CONTINUOUSLY FOCUSABLE MICROSCOPE INCORPORATING AN AFOCAL VARIATOR OPTICAL SYSTEM, and U.S. Pat. No. 4,988,173 entitled MODULAR AFOCAL VARIATOR OPTICAL FOCUSING SYSTEM.
In other known prior art, Hillman U.S. Pat. No. 2,937,570 discloses a telescope system in which the image forming lenses are moved in order to focus the system. That is, focusing is accomplished by moving the objective lens relative to the focusing lens, both of which are part of the telescope's "formula-specific" objective imaging system. Focusing is not accomplished or taught to be feasible by moving a central, modular position of an afocal variator, nor by determining the optical effect of an afocal variator and incorporating its front and rear elements into the image-forming optics, but still retaining a central modular element which is non-image-forming and essentially non-formula-specific.
Matsumura U.S. Pat. No. 4,318,585 discloses an optical system with an afocal focusing group, but in which the afocal focusing group is a Galilean telescope rather than an afocal variator. Furthermore, the system as taught by Matsumura does not incorporate the front, rear or front and rear elements of an afocal variator into the calculation and formulation of the image forming optics.
Quendreff French Patent 2,572,545 teaches the use of a zoom lens to make enlarged pictures, and also teaches the use of various art known mechanical devices for connecting together optical modules. However, it neither teaches nor suggests the use of an afocal variator, nor of a system in which one or more of the outer optical elements of an afocal variator are subsumed into the formula-specific, image-forming optics.
It is thus seen that, while the use of varios and variators have been taught by the applicant in conjunction with front and rear refractive optical systems, and front and rear partially-obscured reflective optical systems, the use of a partial variator system in conjunction with both a front optical system and with a rear optical system, in which either the front optical system, the rear optical system, or the front and rear optical systems provide one or more optical element in conjunction with a partial variator system in order to complete and to form an afocal variator system, has not been previously taught or suggested by the known prior art.